The driver fatality ratio (DFR) proposed by the National Highway Traffic Safety Administration (NHTSA) demonstrates the relative fatality risks of occupants in various vehicle-to-vehicle (VtV) crashes. The readily available DFR is based on statistical crash data; hence, estimating the DFR of occupants for newer fleet of vehicles can be quite difficult. Three systematic methods such as the intrusion, deceleration and stiffness ratios of two colliding vehicles in side-impact accidents are proposed to estimate the DFR. A fleet of light trucks and vans (LTVs) striking a sedan car is reconstructed using the non-linear explicit code, LS-DYNA. The simulation results have shown that the intrusion and acceleration ratios-based approaches are in good agreement with the statistical DFR, whereas the DFR estimated using the stiffness-ratio based approach yielded poor agreement. The intrusion and acceleration ratios-based approaches are then utilized to formulate a combined DFR estimation model. In the second part of the study, the proposed methodology is carried further to estimate the DFR of occupants for a fleet of LTVs impacting a newer passenger car. The proposed methodology can be a viable tool for estimating the DFR for newer road vehicles and to improve its crash compatibility with collision partners.